Landfills are often prolific contributors of greenhouse gases, particularly methane (CH4), which according to the EPA, is a greenhouse gas that is approximately 21 times more potent than carbon dioxide (CO2). As a byproduct of waste disposal and aerobic and anaerobic digestion by microbes of organic matter, landfills produce a variety of gases, including methane and carbon dioxide and others. Some of these gases, typically composed of mostly methane and carbon dioxide, may be collected in compliance with state and federal regulations and combusted in a flare system. However, methane, in particular, may be utilized with contemporary technology to generate electricity by combustion, fuel industrial boilers, or be converted to pipeline quality High-BTU gas so there is inherent value in using methane. In addition to obvious economic advantages derived from using methane as a fuel, flaring methane from the landfill reduces greenhouse gas emissions relative to the situation where methane is neither utilized as a fuel nor flared.
Landfills frequently have gas extraction systems to capture landfill gases. The gases are typically drawn out of a landfill with a low pressure vacuum via a wellfield collection and control system (GCCS). The wellfield typically consists of multiple gas extraction wells that extend deep beneath the surface of the landfill to pull methane from a location near the bottom of the landfill. Each extraction well extends up to the surface of the landfill and is connected with other wells, creating a piping matrix, so that a vacuum can be pulled with one centralized blower or compressor.
Landfill gas extraction wells are perforated along their lengths to allow the gases to be extracted from the waste deposits. There are many factors that influence the effectiveness of a landfill gas extraction well. For example, there may be a liquid-level blockage, insufficient perforation coverage, failed perforations, or non-perforated risers that prohibit the vacuum from being applied to the surrounding waste and therefore decrease the efficiency of gas extraction.
In the instance of a high liquid level, a dewatering pump is often installed in the extraction well to remove the liquid and allow the vacuum to pull on the waste through the perforations again. But in the other three aforementioned instances, there is very little to nothing that can be done to restore the extraction well. Therefore, there is a need for an apparatus and method to restore these poorly performing or non-performing LFG extraction wells.